Magnetometers are instruments used for measuring the strength and direction of various magnetic fields such as the earth's magnetic field. The earth's magnetic field may be utilized to determine, for example, heading of a moving vehicle or a pedestrian. The heading of a moving pedestrian, for example, is defined as the angle formed between the longitudinal axis of the pedestrian and magnetic north. Magnetometers come in many different forms. A magnetometer triad is a magnetometer that is able to measure all three orthogonal components of magnetic field. Readings of the Earth's magnetic field provided by magnetometer triads may be utilized to compute the heading of a vehicle or a pedestrian in motion. Magnetometers may work very well in clean magnetic environments like in the outdoors. However, they may be strongly influenced by magnetic perturbations produced by manmade infrastructure in the indoors, for example. These magnetic perturbations may affect headings derived from magnetic filed measurements of the magnetometers.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.